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martec
martec
New Member
February 18, 2026
Question

Rustdesk connection allowed but no outgoing pakets

  • February 18, 2026
  • 1 reply
  • 177 views

Hello Fortinet Community

We're facing a connection problem with an Fortigate60, on which no connection to any rusdesk Relay is possible. On the Firewall of the Target there is no traffic at all from the source, which means somehow the connection is still blocked. 

 

rusdesk_allowed.png

 

 

 

 

 

Does anyone know what could cause this? 

1 reply

magliano
Staff
magliano
Staff
February 18, 2026

Hi @martec ,

 

If you have the source and destination IP addresses, you can run a sniffer and a debug flow to verify where the packets are being dropped and/or whether the traffic is being allowed by a policy or hitting the implicit deny rule.

 

https://community.fortinet.com/t5/FortiGate/Technical-Tip-Packet-capture-sniffer/ta-p/198313

 

https://docs.fortinet.com/document/fortigate/7.6.6/administration-guide/54688/debugging-the-packet-flow

 

Best regards.

martec
martecAuthor
New Member
March 27, 2026

Thanks for your response. As suggested I activated the debug output:

diagnose debug enable diagnose debug flow filter  daddr <targetip> diagnose debug flow show function-name enable diagnose debug flow trace start 100
... id=65308 trace_id=63 func=print_pkt_detail line=5952 msg="vd-root:0 received a packet(proto=6, <sourceip>:49495-><targetip>:21114) tun_id=0.0.0.0 from v0010-server. flag [S], seq 30018420, ack 0, win 64240" id=65308 trace_id=63 func=init_ip_session_common line=6152 msg="allocate a new session-04ee0678" id=65308 trace_id=63 func=rpdb_srv_match_input line=1173 msg="Match policy routing id=2130837505: to <targetip> via ifindex-32" id=65308 trace_id=63 func=vf_ip_route_input_common line=2612 msg="find a route: flag=04000000 gw-<gw_ip> via v902-inet2-sc" id=65308 trace_id=63 func=__iprope_tree_check line=528 msg="gnum-100004, use int hash, slot=8, len=4" id=65308 trace_id=63 func=fw_forward_handler line=992 msg="Allowed by Policy-72:" id=65308 trace_id=64 func=print_pkt_detail line=5952 msg="vd-root:0 received a packet(proto=6, <sourceip>:49495-><targetip>:21114) tun_id=0.0.0.0 from v0010-server. flag [S], seq 30018420, ack 0, win 64240" id=65308 trace_id=64 func=resolve_ip_tuple_fast line=6054 msg="Find an existing session, id-04ee0678, original direction" id=65308 trace_id=64 func=npu_handle_session44 line=1242 msg="Trying to offloading session from v0010-server to v902-inet2-sc, skb.npu_flag=00000000 ses.state=00010204 ses.npu_state=0x00000000" id=65308 trace_id=64 func=fw_forward_dirty_handler line=442 msg="state=00010204, state2=00000001, npu_state=00000000" id=65308 trace_id=65 func=print_pkt_detail line=5952 msg="vd-root:0 received a packet(proto=6, <sourceip>:49495-><targetip>:21114) tun_id=0.0.0.0 from v0010-server. flag [S], seq 30018420, ack 0, win 64240" id=65308 trace_id=65 func=resolve_ip_tuple_fast line=6054 msg="Find an existing session, id-04ee0678, original direction" id=65308 trace_id=65 func=npu_handle_session44 line=1242 msg="Trying to offloading session from v0010-server to v902-inet2-sc, skb.npu_flag=00000000 ses.state=00010204 ses.npu_state=0x00000000" id=65308 trace_id=65 func=fw_forward_dirty_handler line=442 msg="state=00010204, state2=00000001, npu_state=00000000" id=65308 trace_id=66 func=print_pkt_detail line=5952 msg="vd-root:0 received a packet(proto=6, <sourceip>:49495-><targetip>:21114) tun_id=0.0.0.0 from v0010-server. flag [S], seq 30018420, ack 0, win 64240" id=65308 trace_id=66 func=resolve_ip_tuple_fast line=6054 msg="Find an existing session, id-04ee0678, original direction" id=65308 trace_id=66 func=npu_handle_session44 line=1242 msg="Trying to offloading session from v0010-server to v902-inet2-sc, skb.npu_flag=00000000 ses.state=00010204 ses.npu_state=0x00000000" id=65308 trace_id=66 func=fw_forward_dirty_handler line=442 msg="state=00010204, state2=00000001, npu_state=00000000" id=65308 trace_id=67 func=print_pkt_detail line=5952 msg="vd-root:0 received a packet(proto=6, <sourceip>:49497-><targetip>:21116) tun_id=0.0.0.0 from v0010-server. flag [S], seq 850716129, ack 0, win 64240" id=65308 trace_id=67 func=init_ip_session_common line=6152 msg="allocate a new session-04ee0844" id=65308 trace_id=67 func=rpdb_srv_match_input line=1173 msg="Match policy routing id=2130837505: to <targetip> via ifindex-32" id=65308 trace_id=67 func=vf_ip_route_input_common line=2612 msg="find a route: flag=04000000 gw-<gw_ip> via v902-inet2-sc" id=65308 trace_id=67 func=__iprope_tree_check line=528 msg="gnum-100004, use int hash, slot=8, len=4" id=65308 trace_id=67 func=fw_forward_handler line=992 msg="Allowed by Policy-72:" id=65308 trace_id=68 func=print_pkt_detail line=5952 msg="vd-root:0 received a packet(proto=6, <sourceip>:49497-><targetip>:21116) tun_id=0.0.0.0 from v0010-server. flag [S], seq 850716129, ack 0, win 64240" id=65308 trace_id=68 func=resolve_ip_tuple_fast line=6054 msg="Find an existing session, id-04ee0844, original direction" id=65308 trace_id=68 func=npu_handle_session44 line=1242 msg="Trying to offloading session from v0010-server to v902-inet2-sc, skb.npu_flag=00000000 ses.state=00010204 ses.npu_state=0x00000000" id=65308 trace_id=68 func=fw_forward_dirty_handler line=442 msg="state=00010204, state2=00000001, npu_state=00000000" id=65308 trace_id=69 func=print_pkt_detail line=5952 msg="vd-root:0 received a packet(proto=17, <sourceip>:59432-><targetip>:21116) tun_id=0.0.0.0 from v0010-server. " id=65308 trace_id=69 func=init_ip_session_common line=6152 msg="allocate a new session-04ee0875" id=65308 trace_id=69 func=rpdb_srv_match_input line=1173 msg="Match policy routing id=2130837505: to <targetip> via ifindex-32" id=65308 trace_id=69 func=vf_ip_route_input_common line=2612 msg="find a route: flag=04000000 gw-<gw_ip> via v902-inet2-sc" id=65308 trace_id=69 func=__iprope_tree_check line=528 msg="gnum-100004, use int hash, slot=8, len=4" id=65308 trace_id=69 func=fw_forward_handler line=992 msg="Allowed by Policy-72:" id=65308 trace_id=70 func=print_pkt_detail line=5952 msg="vd-root:0 received a packet(proto=17, <sourceip>:59432-><targetip>:21116) tun_id=0.0.0.0 from v0010-server. " id=65308 trace_id=70 func=resolve_ip_tuple_fast line=6054 msg="Find an existing session, id-04ee0875, original direction" id=65308 trace_id=70 func=npu_handle_session44 line=1242 msg="Trying to offloading session from v0010-server to v902-inet2-sc, skb.npu_flag=00000400 ses.state=00010204 ses.npu_state=0x00000000" id=65308 trace_id=70 func=ip_session_install_npu_session line=368 msg="npu session installation succeeded" id=65308 trace_id=70 func=fw_forward_dirty_handler line=442 msg="state=00010204, state2=00000001, npu_state=00000400" ...

I dont know where to look next. It should work, but it doesn't.

 

diagnose sniffer packet any "host <target_ip>" 4

 

13.752694 v0010-server in <sourcet_ip>.49852 -> <target_ip>.21116: syn 3198382451  13.752752 v902-inet2-sc out <sourcet_ip>.49852 -> <target_ip>.21116: syn 3198382451  13.752757 internal2 out <sourcet_ip>.49852 -> <target_ip>.21116: syn 3198382451  13.770872 v0010-server in <sourcet_ip>.49853 -> <target_ip>.21116: syn 1830517245  13.770919 v902-inet2-sc out <sourcet_ip>.49853 -> <target_ip>.21116: syn 1830517245  13.770923 internal2 out <sourcet_ip>.49853 -> <target_ip>.21116: syn 1830517245  14.752307 v0010-server in <sourcet_ip>.49852 -> <target_ip>.21116: syn 3198382451  14.752334 v902-inet2-sc out <sourcet_ip>.49852 -> <target_ip>.21116: syn 3198382451  14.752339 internal2 out <sourcet_ip>.49852 -> <target_ip>.21116: syn 3198382451  14.770956 v0010-server in <sourcet_ip>.49853 -> <target_ip>.21116: syn 1830517245  14.770977 v902-inet2-sc out <sourcet_ip>.49853 -> <target_ip>.21116: syn 1830517245  14.770981 internal2 out <sourcet_ip>.49853 -> <target_ip>.21116: syn 1830517245  14.774874 v0010-server in <sourcet_ip>.55205 -> <target_ip>.21116: udp 85 14.774917 v902-inet2-sc out <sourcet_ip>.55205 -> <target_ip>.21116: udp 85 14.774921 internal2 out <sourcet_ip>.55205 -> <target_ip>.21116: udp 85 16.727010 v0010-server in <sourcet_ip>.49855 -> <target_ip>.21114: syn 3259890844  16.727109 v902-inet2-sc out <sourcet_ip>.49855 -> <target_ip>.21114: syn 3259890844  16.727114 internal2 out <sourcet_ip>.49855 -> <target_ip>.21114: syn 3259890844  16.753477 v0010-server in <sourcet_ip>.49852 -> <target_ip>.21116: syn 3198382451  16.753507 v902-inet2-sc out <sourcet_ip>.49852 -> <target_ip>.21116: syn 3198382451

 

Any Ideas?

 

Thanks in advance

Best regards.

 

 

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